Vertical muffler for internal combustion engine



C. I. KEENE Dec. 6, 1955 VERTICAL MUFFLER FOR INTERNAL COMBUSTION ENGINE Filed May 14, 1951 2 Sheets-Sheet 1 INVENTOR; CHARLES I. KN

BY 41 4, W Y

ATTORNEYS C. KEENE Dec. 6, 1955 VERTICAL MUFFLER FOR INTERNAL COMBUSTION ENGINE Filed May 14, 1951 2 Sheets-Sheet 2 O QOQOM) OCOO IN V EN TOR.

CHAPLESL KEENE ATTORNEYS United States Patent 2,725,948 Patented Dec. 6, 1955 ice VERTICAL MUFFLER FOR INTERNAL COM'BUSTION ENGINE Charles I. Keene, Cedar City, Utah Application May 14, 1951, Serial No. 226,245 5 Claims. (Cl. ISL-43) This invention relates to an exhaust muffler of the vertical type used with internal combustion engines.

One of the objects of this invention is the provision of a muffler that will last many times longer than the conventional mufflers heretofore used.

Another object of the invention is the provision of a mufller that is more efiicient than the usual mufflers heretofore employed and that increases the horsepower and efiiciency and life of the engine, as compared with the horsepower and the efdciency of an engine that uses a mufiler of the conventional type mainly used heretofore.

A still further object of the invention is the provision of a muffier that reduces the smoke level and that is substantially free from carbon deposit for an indefinite period of time far exceeding the normal life of common muillers heretofore used. This means that the muffler does not loose its efliciency with age or use, and that its life is far longer than is the life of the ordinary mufiler heretofore employed.

it is to be understood that the present muiller is usually used vertically, in large trucks and where the exhaust discharge is rather high.

(lonventional muillers employ an enlarged chamber in the discharge or exhaust conduit into which the gas expands before exhaust. State laws require the use of mufilers, and the conventional mufilers, when new, will normally cause a back pressure of 1.5 inches of mercury, and this is practically the maximum that is permitted. However, shortly after the ordinary mufilers are put into use, the back pressure will run as high as 4 inches of mercury which causes engine trouble, loss of power etc., and the maximum life of the conventional .mufller is limited. it will burn out, requiring replacement.

With the present invention the back pressure has been reduced to from /1 to 1.4 inches of mercury, which figures are the result of actual operations of trucks powered by 275 H. P., Diesel Cummings engines under conditions requiring from fifth direct drive, and with the engine operating at from 1800 R. P. M., to fourth under drive at 2050 R. P. M., at cruising speed and no grade and with the engine operating at 1800 R. P. M., in fifth direct drive, the back pressure developed was only /4 inch of mercury, and on a twelve mile grade, under load, at an engine speed of 2050 R. P. M., with the truck in fourth under drive, the back pressure developed was 1.4 inches.

With this present invention, the life of a muffler is indefinite, with known instances of mufilers in perfect condition without accumulation of carbon after having been used in excess of 50,000 miles.

Other objects and advantages will appear in the description and in the drawings, such as the provision of a structure in which a substantial differential is produced in the temperature of the exhaust gas between the intake and discharge end of the mufller, which differential is up to 300 F., and more.

In the drawings,

Fig. 1 is a vertical sectional, reduced size view of a mufller, a portion intermediate its ends being in elevation.

Fig. 2 is an enlarged sectional view taken along the line 2-2 of Fig. 1.

Fig. 3 is an enlarged fragmentary sectional view of the lower end portion of the muffler, partly in elevation.

Fig. 4 is a reduced size side elevational view of a slightly different form of the invention.

Fig. 5 is a part section, part elevational enlarged view of the mufiler of Fig. 4, with sections removed to accommodate the view to the sheet.

Fig. '6 is a sectional view taken along line 66 of Fig. 4.

Referring to Figs. 1 to-3, the muffler illustrated therein comprises a vertical, tubular outer shell generally designated l, and an inner tube generally designated 2 spaced within shell 1 and coaxial therewith, both the shell and tube preferably being cylindrical.

At the lower end of the shell 1 is a bottom wall 3 through which the tube 2 extends. This bottom wall may be secured to the shell and tube in any suitable manner, such as by welding, and it not only functions to support the lower end of tube 2 in spaced relation within the shell 1, but it closes the lower end of the space between said tube and said shell.

Tube 2 is of uniform diameter for the major portion of its length. However, the upper end portion 4 is of substantially reduced diameter; and upwardly convergently extending Walls 5 connect thereduced upper end portion 4 with the uniform diameter portion of the tube therebelow.

The lower end of tube 2 is adapted to be connected with the exhaust line leading from the engine, hence the hot exhaust gas from the engine will enter the lower end of the tube. 2 for passage therethrough and out of the reduced diameter end portion 4 at a substantially increased velocity. The inclination of the walls 5 is such as to reduce the resistance to movement of the gas therepast as much as possible, as in a Venturi tube.

The upper portion, 6 of the outer shell 1 is also of reduced diameter, and said portion is joined to the remainder therebelow by walls 7 that are substantially parallel with Walls 5 that are spaced inwardly thereof. Spaced spacers 8 between the upper ends of tube 2 and shell 1 space the upper end of said tube concentrically within the upper end of said shell, and the space be tween all portions of the tube 2 and shell 1 is substantially the same.

Itwill be seen from the foregoing construction that the reduced upper end portion 4 of tube 2 projects into the upper end portion 6 of the outer shell 1. The distance that said portion 4 extends into the portion 6 may vary, but it should be such as to insure a suflicient velocity of the gas discharged therefrom to carry the gas out of the portion 6 and to induce a good flow of gas into the portion 6 from the space between the shell 1 and tube 2.

A substantial section of the length of the tube 2 at its lower end is perforated, as indicated by the perforations 10. This section preferably commences at a point spaced slightly above the bottom wall 3 and the upper end portion of the tube 2 is preferably imperforate, and although the length of the perforated zone may vary, there should be an imperforate section, in which the pressure is reasonably constant during operation of the engine.

The larger the volume of gas that must be handled by the muffler, the longer the perforated zone will be.

Just below the lower end of the perforated zone, and spaced above bottom wall 3, are several equally spaced equal sized perforations 11. Usually four of these perforations 11 are adequate, and they are respectively substantially larger in diameter than the diameter of perforations 10. A deflector plate 12 is positioned to extend over each perforation 11. Each deflector plate resembles a gablelike hood having a central ridge 13 (Fig. 2) that extends slantingly downwardly and outwardly from a point directly above each opening, with the sides of each deflection plate at opposite sides of such ridge slanting downwardly from the ridge and extending below the level of the opening 11 at opposite sides of the latter. The angle of the sides of each deflector plate is preferably such that gas ejected through openings 11 will be deflected downwardly in a fan-like shapes that overlap at the bottom wall 3, which gas will impinge the entire upper surface of bottom wall 3. Said deflector plates are of special heat resistant steel and are integrally secured to tube 2, as by welding.

In actual practice it has been found that mufliers of the same dimensions and structure may be used for diesel engines of from about 150 to 300 horsepower. The length of the perforated section of tube 2 may vary, but the general structure otherwise may be the same when used in different sizes and for different fuels.

When the engine is running, the hot exhaust gas will enter the tube 2. A certain portion, will pass straight through the tube and out of the reduced upper end portion 4 and out of portion 6 of shell 1, inducing a flow of gas out of the space 20 that is between the shell 1 and tube 2. The natural expansion of the gas in tube 1, coupled with the reduced pressure in space 20 resulting from the suction developed at and adjacent to the reduced upper end portion 4, will result in the hot exhaust gas passing through the openings 11 and 12 into space 20. Gas at its hottest temperature after entering the muffler will pass through openings 11 and be deflected downwardly, or in a reverse direction to the flow of gas in tube 2 and will not only produce a heated zone 21 between tube 2 and shell 1 at the lower end of space 20, but there will be a substantial turbulence in said zone 21 that will prevent the accumulation of carbon and impurities therein.

In actual practice, the carbon that passes through the openings 11, 12 is burned up or sufficiently reduced in zone 21 to prevent any accumulation from forming that would in any way reduce the efliciency of the mufiler. In over 50,000 miles of actual use, as examination of a muffler showed less than a tablespoon of loose carbon in the space 20.

As already mentioned, the back pressure is not only reduced by use of the muflier, but such reduction is maintained. Where ordinary mufliers start at a back pressure of substantially 1.5 inches of mercury and rapidly become stopped up with carbon until a back pressure of 4 and more inches of mercury is developed, the present muffler will reduce the pressure to form to 1.4 inches of mercury, the latter being under the most adverse conditions for producing a back pressure, while the former represents the most favorable conditions.

This reduction in back pressure is reflected in increased efficiency whereby the truck operator can use from a half to a full gear higher than heretofore, and effect a substantial saving in fuel. By getting the gas out of the cylinders faster, which is a result of reduced back pressure, more air is admitted to the cylinders and there is a cleaner burning of the fuel.

While the structure above described is perhaps most commonly used, the design may be modified as shown in Figs. 4, 5, and 6 for high-output engines and on any equipment in which the muffler is so mounted that it does not have the proper normal circulation of fresh air to aid in the cooling of the gas.

In Figs. 4 to 6 the outer shell 25 is provided that is similar in structure to shell 1 having an enlarged lower end portion 26 and a reduced diameter upper end portion 27 and a tapered frusto-conical section 28 connecting said portions.

The inner tube 29, which is coaxial within shell 25, has an enlarged lower end portion 30 and a reduced diameter upper end portion 31, said portions being connected by a frusto-conical section 32.

The lower ends of the shell has a plate 34 secured thereto, which plate extends thereacross and is formed with a central opening in which the tubular section 35 of slightly lesser diameter than said lower end portion 30, is secured. Said section 35 is adapted to be connected with the exhaust line from the engine.

Spaced above the plate 34, is a bottom wall 36, that functionally corresponds to the bottom wall 3 of Fig. 1, said wall being secured to the lower end of the tube and extending across the space between said tube and shell 25.

It will be seen from the above, that the gas ejected through the tubular section will enter the enlarged expansion chamber 37 that is between plate 34 and bottom wall 36 before entering the lower end of tube 29, and such as will expand in said chamber.

The lower end portion of the tube 29 is perforated as at 38, and like tube 2, said tube 29 is formed with several larger equally spaced perforations 40 (preferably four in number) over which are secured deflector plates 41 that are identical with the deflector plates 12. The perforations 38 may extend to the bottom wall 36 if desired, as indicated in Fig. 5.

in the space 42 between shell 25 and the tube 29 are four equally spaced air tubes 43 that are spaced from the walls of said shell and tube and that extend between adjacent pairs of deflector plates 41. The lower ends of these tubes 43 are secured in openings formed in plate 34 for admitting atmospheric air into them, and they extend through openings formed in the bottom wall 36 to the tapered wall 32 Where they extend convergently and parallel with said wall 32 and into openings formed in a tubular section 45 to which their open upper ends are secured.

Section 45 is of greater diameter than the diameter of the upper end portion 31 of tube 30 and of less diameter than the reduced diameter upper end portion 27 of shell 25. Said section 45 is secured at its lower end to wall 32 and extends upwardly into the portion 27 of shell 25 in spaced relation to the latter and coaxial therewith. The upper portion 31 of tube 29 is spaced within the section 45 and is also coaxial therewith and said upper end preferably terminates within section 45 spaced below its upper and open end, while the upper open end of section 45 is terminated at a point spaced below the upper end of portion 27.

In operation, the gas entering the expansion chamber 37, is expanded therein and then enters the lower perforated end of the tube 29. The action of the gas in this tube is similar to the operation already described for the muffler of Fig. 1, some of the gas passing directly through the said tube and out of the reduced upper end portion thereof at high velocity, and the remainder of the gas passing through the perforations 38, 40 and into space 42.

It will be noted that the passage of the gas out of the upper portion 31 of tube 29 induces a flow of fresh air through tubes 43 into the tubular section 45 where such cool fresh air mixes with the gas ejected into section 45, contracting the gas. The velocity of the gas ejected from the upper end of the section 45 results in inducing a flow of the gas from space 42 into the upper end 27 of shell 25 where it mixes with the cooled gas and is ejected from said portion 27.

It will be seen that a certain cooling of the gas by conduction, will occur in the space 42 through which the tubes 43 extend before the gas reaches the upper portion 27 of shell 25.

The cooling of the gases as above explained, will extend the life of the muflier and the engine.

efras as It is to be understood that the use of the term vertical or vertically in the description and claims does not necessarily restrict the muffler to use in a vertical position. Also, the muffler is not necessarily restricted to truck use nor to use with internal combustion engines of any particular type. Many of its advantages follow from its use on passenger automobiles and in connection with engines using gasoline or butane, as distinguished from those operating only on diesel oil.

I claim:

1. A mufller for an internal combustion engine comprising a vertically extending outer tubular shell open at its upper end and an open ended tube spaced within said shell, a bottom wall closing the space between the lower end portions of said shell and said tube, the lower open end of said tube being adapted to receive exhaust gas from said'engine for discharge from its upper open end into the upper end of said shell and out of the latter, the walls of said tube adjacent to and above said bottom wall being formed with perforations for passing part of said gas into the space between said shell and tube and spaced deflector plates in said space inclined downwardly and outwardly and over said perforations for deflecting the gas passing through the latter downwardly toward said bottom wall, air tubes in the space between said shell and tube extending longitudinally thereof opening at their lower ends below said bottom wall and terminating at their upper ends substantially at the upper end of said tube for conducting an induced flow of air into the upper end of said shell for mixing with said gas before discharge of the latter from the upper end of said shell.

2. A mufller for an internal combustion engine comprising a vertically extending outer tubular shell open at its upper end and an open ended tube spaced within said shell, a bottom wall closing the space between the lower end portions of said shell and said tube, the diameter of the upper end of said shell being less than that of its lower end, the upper end of said tube being of less diameter than the lower end of said tube, the lower open end of said tube being adapted to receive exhaust gas from said engine for discharge from its upper open end into the upper end of said shell and out of the latter, the walls of said tube adjacent to and above said bottom wall being formed with perforations for passing part of said gas into the space between said shell and tube and spaced deflector plates in said space inclined downwardly and outwardly and over said perforations for deflecting the gas passing through the latter downwardly toward said bottom wall, air tubes in the space between said shell and tube ex tending longitudinally thereof opening at their lower ends below said bottom wall and terminating at their upper ends substantially at the upper end of said tube for conducting an induced flow of air into the upper end of said shell for mixing with said gas before discharge of the latter from the upper end of said shell, a tubular member coaxial with said tube connected with the upper ends of said air tubes and into which their said upper ends open, said tubular member being of greater diameter than the reduced diameter upper end of said tube and of less diameter than the diameter of the reduced diameter upper end of said shell and spaced between said reduced diameter ends of said tube and shell.

3. A muflfler for an internal combustion engine comprising a vertically extending outer tubular shell open at its upper end and an open ended tube coaxial with and spaced within said shell, a bottom wall connecting the lower end portions of said shell and said tube and extending across the space between them, the diameter of the upper end portion of said shell being less than that of its lower end portion, the upper end of said tube terminating below the upper end of said shell and being of less diameter than the lower end of said tube and of less diameter than the upper end portion of said shell, the lower open end of said tube being adapted to receive the exhaust gas from said engine for passage through said tube and into and out of the reduced diameter open upper ends of said tube and shell, the walls of said tube above and adjacent to said bottom wall being perforated for passage of some of said gas through and into the space between said shell and tube for upward movement into and out of the reduced upper end portion of said shell, deflector plates in said space inclined downwardly and outwardly from the walls of said tube and over certain of said perforations in the latter for deflecting the gas passing therethrough in a downward direction toward said bottom wall, said plates being spaced from each other for upward passage therepast of the gas therebelow, each of said deflector plates being gable like providing a central ridge and Walls extending divergently from said ridge, one end of the ridge of each plate being directly above each perforation therebelow with said ridge extending slantingly downwardly and outwardly and with said last mentioned walls extending laterally to opposite sides of said perforation and at such an angle to each other to deflect said gas in a fan shape overlapping the gas from the adjacent deflector plates at said bottom wall whereby the deflected gas will impinge the full area of the upper side of said bottom wall to prevent accumulation of unburned carbon therein.

4. A mufller adapted to be mounted upright on a vehicle comprising a vertically extending straight cylindrical inner tube having an inlet at its lower end for receiving exhaust gas from an internal combustion engine and an outlet at its upper end for said gas, said inlet and said outlet being circular and coaxial with said outlet being of smaller diameter than said inlet the walls of said tube being of uniform diameter from said inlet to a point adjacent to and spaced below said outlet and tapered from said point to said outlet, an outer imperforate, cylindrical tubular shell spaced around said inner tube coaxial therewith and projecitng above said outlet at its upper end, the upper end portion of said outer shell above said outlet being of greater diameter than said outlet, but of lesser diameter than the lower end of said tube, a horizontal bottom wall between said tube adjacent to said inlet and the lower end of said shell securing the lower end of said tube and shell together in spaced coaxial relationship, a plurality of openings formed in said inner tube adjacent to and spaced above said bottom wall and downwardly and outwardly inclined imperforate deflectors on said inner tube extending from said tube over said openings terminating at their lower ends above said bottom wall and a substantial distance from the walls of said shell.

5. A mufiler adapted to be mounted upright on a vehicle comprising a vertically extending straight cylindrical inner tube having an inlet at its lower end for receiving exhaust gas from an internal combustion engine and an outlet at its upper end for said gas, said inlet and said outlet being circular and coaxial with said outlet being of smaller diameter than said inlet the walls of said tube being of uniform diameter from said inlet to a point adjacent to and spaced below said outlet and tapered from said point to said outlet, an outer imperforate, cylindrical tubular shell spaced around said inner tube coaxial therewtih and projecting above said outlet at its upper end, the upper end portion or" said outer shell above said outlet being of greater diameter than said outlet, but of lesser diameter than the lower end of said tube, a horizontal bottom wall between said tube adjacent to said inlet and the lower end of said shell securing the lower end of said tube and shell together in spaced coaxial relationship, a plurality of openings formed in said inner tube adjacent to and spaced above said bottom wall and downwardly and outwardly inclined imperforate deflectors on said inner tube extending from said tube over said openings terminating at their lower ends above said bottom wall and a substantial distance from the walls of said shell, said inclined deflectors extending from a point directly above and adjacent to each of said openings and terminating at their lower ends substantially at the level of the lower edge of each opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,760,924 Watkins June 3, 1930 8 Herring et a1. Dec. 29, 1931 Newton Aug. 15, 1939 McLeod June 13, 1950 FOREIGN PATENTS Switzerland Sept. 16, 1937 

